Back in October, Sanford had written a letter to the White House to share her good news. The 48-year-old single mother of a teenage son diagnosed with ADHD had just purchased what she considered to be affordable insurance on the Washington state exchange....

Her heartfelt letter made it to the President's hands and then into his October 21 speech.

"'I was crying the other day when I signed up. So much stress lifted.'" Obama said, reading from Sanford's letter.

The president said Sanford's story was proof, despite the technical problems with the healthcare.gov website, that the Affordable Care Act was working....

But then, after Obama mentioned her story, Sanford started having problems. Sanford said she received another letter informing her the Washington state health exchange had miscalculated her eligibility for a tax credit.

In other words, her monthly insurance bill had shot up from $198 a month (she had initially said $169 a month to the White House but she switched plans) to $280 a month for the same "gold" plan offered by the state exchange....

Last week, Sanford received another letter from the Washington state exchange, stating there had been another problem, a "system error" that resulted in some "applicants to qualify for higher than allowed health insurance premium tax credits."...

The result was a higher quote, which Sanford said was for $390 per month for a "silver" plan with a higher deductible. Still too expensive

A cheaper "bronze" plan, Sanford said, came in at $324 per month, but also with a high deductible - also not in her budget.

Then another letter from the state exchange with even worse news.

"Your household has been determined eligible for a Federal Tax Credit of $0.00 to help cover the cost of your monthly health insurance premium payments," the latest letter said.